The seat recliner is used to connect the seat cushion and the seat back of the seat of vehicle so as to improve the comfort of the seat. A passenger may adjust the angle of the seat back to an optimum position by the seat recliner, so as to obtain a most comfortable and customary seating angle. For a driver, the best visual field may be achieved, and manipulated members such as steering wheel, brake pedal and shift lever are easily manipulated by adjusting the angle of the seat back.
At present, the seat recliner generally includes two types. One type of the seat recliner is a leaf spring type adjusting mechanism on the basis of the principle of the ratchet wheel and pawl mechanism; and the other type of the seat recliner is a gear type adjusting mechanism on the basis of the principle of the planetary gear transmission.
For the gear type recliner on the basis of the principle of the planetary gear transmission, due to the inevitable manufacture error, there is a clearance inside such recliner. In use, this clearance results in a greater swaying of the seat back in forward-backward direction relative to the seat cushion with noise, which in turn affects the comfort of the seat.
In order to eliminate the above-mentioned clearance, the conventional gear type recliner is generally provided with a separate wedge clearance eliminating mechanism, and such mechanism serves as a turning-arm wheel in a planetary gear transmission mechanism with small tooth number difference. However, there are two prominent problems for such structure. One problem is that, since the wedging component is two separate structures and the load is mainly applied on one wedge, the contact portion is substantially deformed due to the concentration of stress, and thus the internal engagement area of gears between movable members and fixed members is decreased, which affects the force state of a single tooth and doesn't fully embody the feature of the high engagement strength of the planetary gear transmission with small tooth number difference. The other problem is that, there is a big space in an eccentric region for such separate wedge clearance eliminating mechanism, thereby causing instable strength and a larger strength fluctuation of the recliner.